GENERATION OF SPATIAL FERTILIZER RECOMMENDATION MAPS OF NETHAKUPPAM WATERSHED USING RS AND GIS
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Date
2019
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ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR
Abstract
A study was undertaken to assess the soil fertility status, delineate the spatial variability of soil fertility status in order to suggest spatial fertilizer recommendation for Nethakuppam watershed of Ramachandrapuram mandal in Chittoor district of Andhra Pradesh state using Remote Sensing and GIS techniques.
Composite surface soil samples (0-15 cm) were collected across the Nethakuppam watershed using Arc map software with the grid size of 10ha. The GPS data at each sample location was recorded. Ground truth analysis indicated that soils of the study area are slightly acidic to strongly alkaline with safe EC range. The available nitrogen content of the soils varied from 25-201kg ha-1, with a mean value of 75 kg ha-1 and standard deviation of 28 with CV of 37 per cent. The available phosphorus status in soils was medium to high and ranged from 16-245 kg ha-1, with a mean value of 62 kg ha-1 and standard deviation of 37 with CV of 59 per cent. The available potassium content in soils of Nethakuppam watershed ranged from 243 to 845 kg ha-1, with a mean value of 388 kg ha-1 with standard deviation of 91 and CV of 24 per cent, the available manganese, copper, sulphur and magnesium content showed much variation with high coefficient of variation. Soils vary across fields and within the fields.
It can be inferred that when average content of micronutrients is observed, soils exhibit sufficient status of micronutrients but the coefficient of variation for available Fe, Cu, Zn and Mn is 71, 90, 92, 65 per cent respectively. The larger CV depicts that within a watershed there is much variation in the micronutrient status, proving that soil fertility is not homogeneous. Spatial variability of soil properties was studied and maps were generated using geo-statistics. In the present study the variability is observed in case of all the nutrients under study with more variation in
manganese followed by copper, sulphur, magnesium, iron and zinc.
The soil site suitability maps for rice, sugarcane and groundnut delineate the areas in to suitable and not suitable which could be utilized for selecting the proper cropping pattern at local level. Suitability analysis of rice crop in study area indicated 92 ha is highly suitable (S1), 648 ha is moderately suitable (S2) and 1508 ha is marginally suitable (S3). The remaining area of 23 ha is having severe limitations that preclude the growing of rice making it not suitable (N). Suitability analysis of sugarcane crop in Nethakuppam watershed indicated that about 880 ha is highly suitable (S1), 1386 ha is moderately suitable (S2). Suitability analysis of groundnut crop in Nethakuppam indicated that about 1713 ha is highly suitable (S1), 526 ha is moderately suitable (S2) and the remaining area of 23 ha is marginally suitable (S3).
Site specific fertilizer recommendations for rice, sugarcane and ground nut in Nethakuppam watershed are made utilizing the thematic maps of spatial variability of N, P and K status. The recommended doses of nitrogen for rice crop is 73, 82, 91 and 101 kg ha-1, recommended doses of phosphorus are 8, 18, 45, 54, 64, 73, 82 and 91 kg ha-1 and the recommended doses of potassium are 5, 15, 25 and 35 kg ha-1. The recommended doses of nitrogen for sugarcane crop is 138, 190, 242 and 294 kg ha-1, recommended doses of phosphorus are 30, 47, 54, 84. 113 and 141 kg ha-1 and the recommended doses of potassium are 65, 81, 94, 108 and 121 kg ha-1. The recommended doses of nitrogen for groundnut is 344, 363, 379 and 383 kg urea ha-1. The recommended doses of phosphorus are 251, 273, 295, 318, 340, 362, 384, 406 and 428 kg SSP ha-1 and the recommended doses of potassium are 196, 200, 204, 208, 212 and 214 kg MOP ha-1.The application of N, P, and K as per the above recommendation in different spatial zones arrived reveals that there is a significant reduction in fertilizer application when compared to the general recommendations.
In conclusion, it can be summarized that new technologies of remote sensing, GIS and GPS have opened a new era in generating natural resource database to integrate and assess their potential on spatial basis. In the present study was highly useful in generating the soil suitability assessment, spatial fertilizer recommendation maps, soil quality assessment and preparation of customized fertilizer formulations. These studies can be made up to village level for micro level management of crop fields which help in attaining sustainability by catering the actual requirement of soil and crop within spatially variable fields. Further, the results provide actual estimates of fertilizer requirement for the study area for the important crops grown, thereby saving budget on nutrients at both planning and farmers level.
Description
D5882
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